Angie Benedetto
December 12, 2016
Introduction
About seventy percent of
women with high blood pressure during pregnancy will develop pre-eclampsia,
this condition can describe mild hypertension as well as severe hypertension
with end-organ dysfunction including high levels of protein in the urine,
eclampsia, hemolysis, higher liver enzymes, and low platelet count (HELLP)
syndrome (Ghulmiyyah et al., 280). The true reason for this condition is
unknown although there are some theories and identified symptoms that could
help improve maternal and fetus mortality and morbidity, some theories of the
cause of pre-eclampsia suggest “inadequate endovascular remodeling of uterine spiral
arteries, immunologic intolerance between fetoplacental and maternal tissues,
maladaptation to cardiovascular changes, excess inflammatory changes of
pregnancy, abnormal angiogenesis, genetic abnormalities…” (Ghulmiyyah et al., 281).
To understand this
condition, we should understand that there are two stages to pre-eclampsia:
early-onset pre-eclampsia and late-onset pre-eclampsia, this is imperative
since research suggests that early-onset and late onset could be attributed to
different factors. Early-onset pre-eclampsia, which occurs before 34 weeks of
gestation, has been associated with poor placental implantation leading to
chronic placental insufficiency with inflammatory factors guiding to
hypertension. Late-onset pre-eclampsia, which develops at 34 weeks of gestation
or after, has been classified as placental disease as well as the result of
maternal metabolic and cardiovascular risk factors (K. Durst et al. 651 e1).
Even though the reason
for this condition is not completely known, are there any ways to prevent this
gestational disease? The purpose of this research paper is to investigate
possibilities on pre-eclampsia prevention. It will discuss the relationship of
pre-eclampsia with severe features of mothers’ BMI during pregnancy, dietary
factors that could help prevent the disease, supplements, and physical
exercise.
Discussion
Pre-eclampsia has been
studied in many countries by various scientist, experiments correlating this
disease and women’s body weight have been made at different times in history.
Obesity affects approximately one third of reproductive-aged women, increasing
rates of obesity may contribute to a higher incidence in hypertensive disorders
among pregnant women (K. Durst et al). According to a study made in the
Department of Obstetrics and Gynecology at Washington University of St. Luis
where 10,196 women were involved it was determined that late-onset
pre-eclampsia with severe features does have a correlation with Body Mass Index
(BMI).
The study consisted of
1473 of normal BMI (18.5-24.9), 3081 overweight women (25-29.9 BMI), 4196 obese
women (30-39.9 BMI), and 1446 of morbidly obese women (BMI greater than 40). Of
all patients 1119 women (11%) developed preeclampsia, out of the women whom
developed the condition eight hundred and one patients (8.6%) developed severe
features. Since there has been evidence in previous studies that early-onset
pre-eclampsia and late-onset pre-eclampsia could be triggered by different
pathogenesis, the cases were separated by the incidence during early onset (339
women) and late onset (542 women). For the early-onset pre-eclampsia no
relation between obese and overweight BMI and risk of pre-eclampsia with severe
features was noted, also when looking at the total cohort there was no
significant trend. On the other hand, when looking only at the results of
late-onset pre-eclampsia there was a trend that indicated BMI and severe
symptoms are correlated. For late-onset pre-eclampsia with severe features there
were 2.9% of normal BMI women, 4.5% of overweight women, 6.2% obese women, and
6.8% were morbidly obese women; these results support that there is a statistically
significant relationship between BMI and the development of late-onset
pre-eclampsia with severe features. This experiment shows the importance of
having a healthy BMI at the time of conceiving and throughout pregnancy.
Although a real
preventitive solution for pre-eclampsia does not exist, the condition is widely
studied and several methods to prevent it have been tried such as dietary
recommendations, cardiovascular drugs, antioxidants, and antithrombotic drugs
(prevention of blood clots).
Under dietary
recommendations a low salt diet is advise, fish oil supplementation, and
calcium supplementation; these three factors were studied with several trials.
A study performed by Steegers et al. suggested that no sufficient evidence was
found to determine that a low salt diet will help in the prevention of
pre-eclampsia. Also, a different study showed that prescribing a low sodium
diet is not beneficial to reduce the rate of pre-eclampsia (Knuist et al.).
Although many sources claim that fish oil reduce inflammatory-mediated vascular
disease, a European study conducted by Olsen et al. where a comparison between
fish oil and olive oil effects in pregnant woman at high risk of pre-eclampsia showed
no significant difference in symptoms of hypertension or pre-eclampsia. A
different study found that pregnant women who ingested large amounts of fish
oil during early pregnancy actually contributed to the increase risk of
hypertensive disorders therefore high supplementary fish oil during pregnancy
is not a valid prevention factor for pre-eclampsia (Sibai et al). During a
research, Belizan et al. studied calcium as a means to prevent pre-eclampsia,
they found that calcium supplementations reduces maternal blood pressure and
although the reason for this is unknown these scientist suggested that calcium
influences parathyroid hormone release and intracellular calcium availability;
but the United States Food and Drug Administration concluded that the
relationship between calcium and decreased maternal blood pressure is
inconsistent and inconclusive, and the amount of calcium to be given in calcium
deficiency population for it to cause and effect would be fairly high.
Diuretics have also been
studied in the prevention of pre-eclampsia as cardiovascular drugs, women given
diuretics had a decreased occurrence of edema and hypertension but not of
pre-eclampsia. Unfortunately, these studies did not have enough participants to
determine a sure answer to whether or not diuretics do help in the prevention
of pre-eclampsia (Sibai et al. 215).
There is evidence that
increased free radical oxidants in plasma could be a reason to develop
pre-eclampsia, this is why vitamin C and E as antioxidants have been studied
since these naturally occurring vitamins help lower Low-Density Lipoprotein
(LDL) oxidation and reduce both superoxide formation and cytokine production,
unfortunately, in different studies the results could not be linked to benefits
of using antioxidants as a means of pre-eclampsia prevention.
On the other hand low
doses of Aspirin was used in studies as an antithrombotic agent, The Paris
Collaborative Group developed 31 randomized trials with 32,217 women, and they
found that the risk of developing pre-eclampsia was slightly reduced for those
women who were given aspirin (Sibai et al. 217).
It is known that exercise
is an effective way to lower high blood pressure in non-pregnant individuals,
for this reason it has been study as a prevention and control of hypertension
and pre-eclampsia during pregnancy. Two identical studies by the University of
Oregon and University of Minnesota showed that exercise during pregnancy
improves angiogenic balance, but it does not help to reduce hypertension in
rats. Even though this experiment showed no difference in blood pressure, it
did show improvement of angiogenic balance, and it is known that angiogenic
imbalances lead to decreased vascular endothelial function and health,
systematic oxidative stress, renal dysfunction, and high blood pressure (Banek
C.). It was determined that exercise
before pregnancy and during pregnancy could help with reduce blood pressure;
although molecular explanations for this is not known.
Conclusion
Pre-eclampsia and
eclampsia have been affecting pregnant women for many years. Before pre-eclampsia
was determined by symptoms of high blood pressure and high protein levels in
urine, it was hard to draw the line between these two conditions, ending in
women having seizures. Pre-eclampsia has earned the recognition of a mysterious
disease, and the only “real” cure is the induced delivery of the child. To
manage it doctors first look at the severity of the symptoms, then the fetal
gestational stage, maternal and fetal status, presence of labor, and last they
consider the wishes of the mother; all these play a factor at the decision of
doctors. A lot of research and medical trials are still needed to understand
more about this disease, but according to my research one of the best ways to
prevent this condition is to start off by being healthy before getting
pregnant, doing regular exercise before and during pregnancy, and maintaining a
healthy BMI. Although a low salt diet, fish oil, and antioxidants did not prove
to be effective, I would agree that maintaining a healthy diet will contribute
not only to the prevention of pre-eclampsia but also to other conditions that could
lead to this disease. More research is needed to understand the cause, cure,
and prevention of pre-eclampsia.
